The byelection will also be a first test of how the Conservatives intend to face up to the threat of Ukip following David Cameron's commitment to an EU referendum. Meanwhile, Labour's John O'Farrell is touting himself as the only alternative to a coalition candidate.

We also hear from Peter Kellner, the president of polling firm YouGov. He says that while smart money may be on the Lib Dems, he would not be surprised if next week's result was very close. He also tells us there are several omens from the infamous Newport byelection of 1922 that contributed to the end of the last Liberal/Tory coalition.

Also this week, as Labour's Ed Miliband throws his weight behind a "mansion tax", we look at whether such wealth taxes really raise revenue - and whether they command popular support.

Plus: money's too tight to mention for George Osborne who was dealt another blow this week. The auction of 4G phone licences raised significantly less cash than he'd hoped leaving his borrowing figures for next month's budget in further trouble.